sbus: convert drivers/sbus/char/* to use module_platform_driver()

This patch converts the drivers in drivers/sbus/char/* to use the
module_platform_driver() macro which makes the code smaller and a bit
simpler.

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/sbus/char/envctrl.c b/drivers/sbus/char/envctrl.c
index be7b4e5..339fd6f 100644
--- a/drivers/sbus/char/envctrl.c
+++ b/drivers/sbus/char/envctrl.c
@@ -1138,16 +1138,6 @@
 	.remove		= __devexit_p(envctrl_remove),
 };
 
-static int __init envctrl_init(void)
-{
-	return platform_driver_register(&envctrl_driver);
-}
+module_platform_driver(envctrl_driver);
 
-static void __exit envctrl_exit(void)
-{
-	platform_driver_unregister(&envctrl_driver);
-}
-
-module_init(envctrl_init);
-module_exit(envctrl_exit);
 MODULE_LICENSE("GPL");